Scoring on Used Thiels here

2.3s on US audiomart look very nice. Would only have to ship a few hundred miles....

They are big though. Probably more obtrusive than I’d like in that room.

They have to go in a particular location in that room, would be very close to rear wall and with an even taller solid wood cabinet immediately to the right, and on either side of a big screen TV sitting on a very solid but open wood stand. Not ideal for those I suspect. This is a second system after all in our family room and things need to not be obtrusive.

The cs1.6s would fit in nicely I think. I could just keep the sub. OR maybe hold out for 1.7s?

Gotta get it right. No rush.  What I have now sounds very good, but you know how it goes....

Thiel recommended at least 1' from the rear wall, at least 3' from side walls, and at least 8' from the listening position. Thiel recommended ideally, 3' from the rear wall, 5' from the side walls and 10' (he measured at 3 meters) from listening position. The little SCS's with their single co-axial driver was the most forgiving in this regard. Listening height is more of an issue (like most dynamic time coherent designs) than with other designs.

Go for it! mapman
excellent speaker traits and characteristics as above. I chose Thiel speakers for their inherently rich timbre of different instruments. The CS 2.4 is a real sweet spot in the modern line. I cannot comment on more vintage models. Keep me posted on the models that you audition.
Happy Listening!

Somewhat tight but the placement for 2.3 as unsound describes would probably work well enough.   SCS would be an easy swap using my current monitor stands there. WAF of SCS probably better but I’d like to find a way to go more full range and squeeze 2.3 or 2.4 in there somehow.

Mapman, both the 2.3's and 2.4's drop below 3 Ohms. Bel Canto suggests a minimum load of 3 Ohms per channel for the C5i.